CN111183296A

CN111183296A - Constant velocity universal joint

Info

Publication number: CN111183296A
Application number: CN201880047309.2A
Authority: CN
Inventors: D·克林斯
Original assignee: Neapco Intellectual Property Holdings LLC
Current assignee: Neapco Intellectual Property Holdings LLC
Priority date: 2017-08-15
Filing date: 2018-08-14
Publication date: 2020-05-19
Anticipated expiration: 2038-08-14
Also published as: CN111183296B; DE102017118605A1; DE102017118605B4; WO2019034636A1; US11536319B2; US20210088083A1

Abstract

The invention relates to a constant velocity universal joint (10) for transmitting torque, comprising: a joint outer portion (20) having a plurality of outer ball tracks (21; 22); a joint inner portion (30) having a plurality of inner ball tracks (31; 32); torque-transmitting balls (40; 41) which are each guided in a track pair formed by the outer ball track (21; 22) and the inner ball track (31; 32); and a cage (50) which accommodates the balls (40; 41) in cage windows (51; 52) and which holds the balls in a common joint center plane (E) in the event of straightening of the constant velocity universal joint (10). In the case of a bend of the joint, the cage keeps the balls in a constant velocity plane at all times. In the case of a straightened constant velocity universal joint (10), the center lines (Si; Sa) of the outer ball tracks (21; 22) and the inner ball tracks (31; 32) of a track pair intersect at an intersection point (S) and are in this case not mirror-symmetrical with respect to a mirror plane (Z) through this intersection point (S), wherein the mirror plane (Z) lies in or is parallel to the joint center plane (E). An inner section (31i) of the centre line (Si) of the inner ball track (31; 32) is wider with respect to the longitudinal axis (La) of the joint outer portion (20) than an outer section (21a) of the centre line (Sa) of the outer ball track (21; 22).

Description

Constant velocity universal joint

Description of the drawings:

the present invention relates to a constant velocity universal joint for transmitting torque according to the preamble of claim 1.

A constant velocity universal joint is a mechanical coupling that connects two shafts to each other, in which the rotational speed of the output shaft is equal to the rotational speed of the input shaft, regardless of the bending angle of the joint. In this case, the constant velocity universal joint comprises a joint outer part having a plurality of outer ball tracks, a joint inner part having a plurality of inner ball tracks and torque-transmitting balls which are guided in track pairs consisting of the outer ball tracks and the inner ball tracks, respectively. Furthermore, a cage is provided which accommodates the balls in cage windows and which holds the balls in a common joint center plane in the event of the constant velocity universal joint being straightened. In the case of a curved joint, the cage keeps the balls always in a constant velocity plane (homokineticischebe). In this case, the spherical outer surface of the cage abuts with clearance against the spherical inner surface of the joint outer part, while the spherical inner surface of the cage abuts with clearance against the spherical outer surface of the joint inner part, in order thereby to achieve a free rotation of the cage between the two joint parts.

In the case of the joints being bent at an angle, the balls move inwardly and outwardly in the respective ball tracks while the balls are held in a common plane by the cage. In this case, a reliable and low-noise transmission of the torque of the input shaft to the output shaft is to be ensured, even in the case of large angular bends. For this purpose, the path of the ball track can be selected accordingly, wherein it has proven to be advantageous to form the ball track from a plurality of segments having different curvatures. In order to achieve an angular curvature which is as large as possible, it is known, for example, for the concavely curved ball tracks of the outer part of the joint to widen in the direction towards the open side of the joint. This widening may be implemented linearly, for example as described in US6,431,988B1. In contrast, DE19706864C1 discloses a constant velocity universal joint in which a convex outer section is connected to a concave inner section in an outer ball track.

By this measure, a large bending angle of up to 53 ° or even 54 ° can be achieved, since the balls can partially protrude from the joint outer part while being held by the cage. However, the constant velocity universal joint having the outer ball tracks that widen in the direction toward the joint opening is prone to generate noise. Since axial air gaps are additionally provided in the region between the outer part of the component joint, the cage and the inner part of the joint, an increased play between the balls and the ball tracks results in a region of greater joint curvature.

The object of the present invention is to provide a constant velocity universal joint which is capable of achieving a large bending angle in the range of 54 ° with as little noise as possible.

According to the invention, this object is achieved by a constant velocity universal joint according to independent claim 1. Advantageous developments of the constant velocity universal joint result from the dependent claims 2 to 13.

It should be noted that the features listed individually in the claims can be combined with one another in any technically expedient manner and represent further embodiments of the invention. The specification further features and describes the invention, particularly in conjunction with the accompanying drawings.

The constant velocity universal joint for transmitting torque according to the present invention comprises a joint outer part having a plurality of outer ball tracks, a joint inner part having a plurality of inner ball tracks, and balls for transmitting torque, each ball being guided in a track pair consisting of an outer ball track and an inner ball track, respectively. Furthermore, a cage is provided which accommodates the balls in cage windows and which holds the balls in a common joint center plane E in the event of straightening of the constant velocity universal joint. In the case of an angled bend of the joint, the cage holds the balls in a constant velocity plane. The joint outer portion has a longitudinal axis La, and an opening and a connecting portion that are axially opposite each other. It is preferably a ball type constant velocity universal joint. In the axial direction, one side of the opening of the joint is referred to as "outer", and one side of the connecting portion is referred to as "inner".

The outer ball track of the outer portion of the joint has a centerline Sa and a track base line extending equidistantly therefrom, while the inner ball track has a centerline Si and a track base line extending equidistantly therefrom. In this case, the center line Sa of the outer ball track has at least one concavely curved inner section and outer sections respectively opposite the inner section, which widen in the direction of the opening of the joint outer part and relative to the longitudinal axis La of the joint outer part. The path curve of the outer ball track therefore widens in the direction of the joint opening. Correspondingly, the center line Si of the inner ball track has at least one convexly curved outer section and inner sections respectively opposite the outer sections, which widen in the direction of the connection of the joint outer part and relative to the longitudinal axis La of the joint outer part. In this case, the segment-by-segment concave and convex paths of the center line of the ball tracks are produced when the joint is straightened and in the viewing direction in the radial direction of the respective ball track.

Therefore, the inner ball track widens in a direction toward the connecting portion as does the outer ball track widening in a direction toward the joint opening. In the sense of the invention, this means that in the outer section of the outer ball track the distance between the respective center line or track base line and the longitudinal axis La of the outer part of the joint increases in the direction towards the joint opening. Accordingly, in the inner section of the inner ball track, the distance between the respective center line or track base line and the longitudinal axis Li of the joint inner part increases in the direction towards the connection part. Thus, when the joint is bent, the balls are always held between the two ball tracks of the track pair. However, the widening of the outer ball track preferably starts at a relatively far outer portion, that is to say in the rear region of the joint journal.

In the case of a constant velocity universal joint which is bent to the greatest extent, the balls contact an outer section of the outer ball track and an inner section of the inner ball track of the ball track. Between the concave inner section of the outer ball track and its outer section, and between the convex outer section of the inner ball track and its inner section, further track sections may be provided. It may be a straight or curved section. The outer section and the inner section can also be connected to further track sections, which are embodied straight or curved. The centre line of the ball track thus consists of a plurality of curved or curved and straight segments. In this case, the radius of the curved segment and the slope of the straight segment may vary throughout the ball track. Thus, the ball tracks may have other inner or outer sections. However, for the purposes of the present invention, the inner section of the inner ball track and the outer section of the outer ball track are defined in such a way that they are sections in the region of which the balls come into contact with the outer ball track and the inner ball track of the track pair with maximum deflection of the constant velocity universal joint.

However, according to the present invention, the outer ball track is not widened to the same extent as the inner ball track. In contrast, the invention provides that, in the case of a straightened constant velocity universal joint, the center lines of the outer and inner ball tracks of the track pair intersect at an intersection point S and are in this case not mirror-symmetrical with respect to a mirror plane Z passing through this intersection point S. In this case, the assumed mirror plane Z is located in or parallel to the joint center plane E. The track curve of the inner ball track is therefore not a direct mirror image of the track curve of the outer ball track, as is the case in the known constant velocity joints with mirror-symmetrical track curves.

In this case, the difference between the trajectories of the center lines of the ball tracks of the track pairs is that the inner section of the center line Si of the inner ball track is widened more than the outer section of the center line Sa of the outer ball track with respect to the longitudinal axis La of the outer part of the joint, or that the outer section of the center line Sa of the outer ball track is widened less than the inner section of the center line Si of the inner ball track. It is thus achieved that in the case of a strong bending of the joint (in particular in the case of a joint which is bent to the greatest extent), the distance between the outer and inner ball tracks of the track pair is reduced, so that the play of the balls at this location is reduced. This reduces the occurrence of negative noises and prevents possible knocking, particularly during cornering. At the same time, large bending angles of up to 54 ° can be achieved.

However, in this case, the trajectories of the inner and outer trajectory curves may be different from each other in other partial regions. The different widening of the inner and outer ball tracks can be achieved in different ways. In contrast to the previously known embodiments, in which the outer section of the outer ball track and the inner section of the inner ball track are widened to the same extent, it can be provided, for example, that the widening of the inner section of the inner ball track is increased. Alternatively, the widening of the outer section of the outer ball track may also be reduced.

For example, in one embodiment of the invention, it is provided that the outer section of the center line Sa of the outer ball track and the inner section of the center line Si of the inner ball track widen linearly with respect to the longitudinal axis La of the joint outer part. Thus, an angle Alpha a is formed between the outer section of the outer ball track and the longitudinal axis La of the outer part of the joint. An angle Alpha i is formed between the inner section of the inner ball track and the longitudinal axis Li of the inner part of the joint. In order to widen the straight outer section of the outer ball track more than the straight inner section of the inner ball track, it is provided that the slope of the inner section of the centre line Si of the inner ball track is greater than the slope of the outer section of the centre line Sa of the outer ball track with respect to the longitudinal axis La of the outer part of the joint. In this case, angle Alpha a is smaller than angle Alpha i.

In addition to different slopes, different widening can also be achieved by an axial shift of the starting point of the inner or outer section. In one embodiment of the invention, it is provided that, in the case of the joint being straightened and when a mirror image of the center line Si of the inner ball track is made on the mirror plane Z, the entire mirror image inner section of the mirror image center line Si' of the inner ball track is situated closer to the connecting section than the entire outer section of the center line Sa of the outer ball track. Thus, the mirror-image inner section of the inner ball track is displaced in parallel along the longitudinal axis La, Li, i.e. in the direction of the connecting portion of the joint, with respect to the outer section of the outer ball track. The widening of the linear inner section of the inner ball track then starts closer to the intersection point S than the outer section of the outer ball track. In this case, there may be only such a parallel shift, or further the slopes of the straight inner and outer segments are different from each other.

In a further embodiment of the invention, it is provided that the outer section of the center line Sa of the outer ball track widens curvedly with a radius Ra and the inner section of the center line Si of the inner ball track widens curvedly with a radius Ri. In order to widen the curved outer section of the outer ball track more than the curved inner section of the inner ball track, it can be provided, for example, that the radius Ri of the inner section of the center line Si of the inner ball track is smaller than the radius Ra of the outer section of the center line Sa of the outer ball track. In this way, the inner section of the inner ball track is bent more than the outer section of the outer ball track.

Alternatively or additionally, in the case of curved inner and outer sections, it can also be provided that the different widening is achieved by an axial displacement of the starting point of the inner or outer section relative to the intersection S. For example, in one embodiment of the invention, it is provided that, in the case of a straightened joint and when a mirror image of the center line Si of the inner ball track is made on the mirror plane Z, the entire mirror image inner section of the mirror image center line Si' of the inner ball track is situated closer to the joint than the entire outer section of the center line Sa of the outer ball track. Therefore, in this case, when the mirror image of the center line Si of the inner ball track is made on the mirror plane Z, the center of the circle to which the radius Ri of the mirror image inner section of the mirrored center line Si' of the inner ball track belongs is at a closer portion to the joint than the center of the circle to which the radius Ra of the outer section of the center line Sa of the outer ball track belongs, because the mirror image inner section of the inner ball track is generally at a closer portion to the joint than the outer section of the outer ball track. However, this is also the case if the curved inner section of the inner ball track starts at the same point as the outer section of the outer ball track when the mirror image is made on the mirror plane Z, but the inner section of the inner ball track is turned in a direction towards the connecting portion of the joint. Furthermore, a movement of the inner section of the inner ball track and such a rotation in the direction of the connecting portion can be provided simultaneously.

In one embodiment of the invention, the constant velocity universal joint has a cage offset. In this case, the longitudinal axis La of the joint outer portion and the joint center plane E intersect at the joint center O. The cage has a spherical cage outer surface and a spherical cage inner surface. The spherical cage outer surface is in surface contact with the spherical joint inner surface of the joint outer portion, and the spherical cage inner surface is in surface contact with the spherical joint outer surface of the joint inner portion. To achieve cage offset, the centers of the spherical cage inner surface and the spherical cage outer surface are located on the longitudinal axis La on opposite sides of the joint center O. In particular, in this case, the spherical cage inner surface and the spherical cage outer surface are at the same distance from the joint center O.

In another embodiment of the invention, the constant velocity universal joint has a ball track offset. The ball track offset is given by: that is, with the joint straightened, the centers of the concave inner section of the outer ball track and the convex outer section of the inner ball track are located on the longitudinal axis La on opposite sides of the joint center O. The ball track offset may also be combined with the cage offset. In this case, the centers of the concave inner section of the outer ball track and the convex outer section of the inner ball track are preferably at a greater distance from the joint center O than the centers of the spherical cage inner surface and the spherical cage outer surface, respectively.

Overall, a constant velocity universal joint can thus be provided, by means of which a large bending angle of 54 ° can be achieved, wherein the generation of disadvantageous noise is reduced. In this case, compared to a joint having mirror-symmetrical tracks of the outer ball track and the inner ball track, no changes have to be made to the installation space of the joint. Furthermore, the actual intermediate shaft diameter can be used and the outer diameter of the joint can be further reduced compared to known joints with large bending angles. The invention can be used in constant velocity universal joints having different numbers of balls.

Further advantages, features and advantageous refinements of the invention emerge from the dependent claims and the following description of preferred embodiments with the aid of the drawing.

In the drawings:

fig. 1 shows a longitudinal sectional view of an embodiment of a constant velocity joint according to the invention being straightened in a straightened state;

FIG. 2 shows the constant velocity joint of FIG. 1 with a mirror image trace of the inner section of the inner ball track attached;

fig. 3 shows a longitudinal section through the constant velocity joint according to fig. 1 with the joint being bent to the greatest extent;

fig. 4 shows the curved constant velocity joint according to fig. 3 with different angles of the centre lines of the inner and outer ball tracks relative to the longitudinal axis Li and La;

FIG. 5 shows a first embodiment of the trajectory of the centerlines of two ball tracks having a pair of linearly widened tracks;

FIG. 6 shows a second embodiment of the trajectory of the centerlines of two ball tracks with curved widened track pairs;

FIG. 7 shows the trajectory according to FIG. 5, accompanied by a mirror image centre line of the inner ball track;

FIG. 7 shows a third embodiment of the trajectory of the centerlines of two ball tracks having linearly widened track pairs;

FIG. 8 shows a fourth embodiment of the trajectory of the centerlines of two ball tracks having linearly widened track pairs;

FIG. 9 shows a fifth embodiment of the trajectory of the centerlines of two ball tracks having linearly widened track pairs;

FIG. 10 shows a fourth embodiment of the trajectory of the centerlines of two ball tracks with curved widened track pairs;

FIG. 11 shows a fifth embodiment of the trajectory of the centerlines of two ball tracks with curved widened track pairs;

fig. 12 shows a front view of the constant velocity universal joint of fig. 1 on the open side with the joint straightened;

3 fig. 3 13 3 shows 3 a 3 cross 3- 3 sectional 3 view 3 a 3- 3 a 3 through 3 the 3 constant 3 velocity 3 universal 3 joint 3 of 3 fig. 3 12 3; 3 And

fig. 14 shows a front view of the constant velocity universal joint of fig. 1 on the opening side with the joint maximally bent.

The constant velocity universal joint 10 shown in fig. 1 is designed in a known manner and is shown in a straightened position, that is to say in the case of a bending angle Omega of 0 °. For the sake of simplicity, the constant velocity universal joint 10 is also referred to below simply as a joint. The fitting 10 has a fitting outer portion 20 and a fitting inner portion 30. Between the joint outer part 20 and the joint inner part 30, a cage 50 is provided, which has cage windows distributed over the circumference of the cage 50. In each case one torque-transmitting ball is accommodated in each of these cage windows, wherein two

balls

40 and 41, which lie opposite one another, can be seen in fig. 1 in the two

cage windows

51 and 52. In this embodiment of the constant velocity universal joint 10, a total of six balls are accommodated in the cage, as can be seen in the views of fig. 12 and 14. In the case of a straightened joint, the centre of the balls lies in a joint central plane E which extends at an angle of 90 ° to the longitudinal axis La of the joint outer part 20 and the longitudinal axis Li of the joint inner part 30.

The joint outer part 20 is hemispherical (as is the case with a joint pin) and is connected via the bottom to the connecting part 61. The connecting portion 61 is formed by a joint pin, which can be connected to a shaft (not shown). The opening 60 of the joint outer portion 20 (and the joint 10 as a whole) is disposed axially opposite the connecting portion 61. The joint inner part 30 and the cage 50 with the

balls

40, 41 are introduced into the joint outer part 20 through this opening 60. The joint inner part 30 is provided with inner longitudinal teeth into which a shaft with external teeth can be inserted in order to thereby form a shaft-hub connection (not shown) that transmits torque.

Two of the plurality of circumferentially distributed outer ball tracks 21 and 22 are shown on the joint outer part 20, while two of the plurality of circumferentially distributed inner ball tracks 31 and 32 are shown on the joint inner part 30. The description of these ball tracks applies analogously to the other ball tracks, which are preferably designed in the same way. Ball tracks 21 and 31 form a track pair for receiving ball 40, while ball tracks 22 and 32 form another track pair for receiving ball 41. In a section along the joint center plane E, the ball tracks have a trough-shaped cross section, as can also be seen in fig. 12. For example, the outer ball track 21 has a track base line 23, while the inner ball track 31 has a track base line 33. The same applies to track base line 24 of outer ball track 22 and track base line 34 of inner ball track 32.

For the outer ball track 21 and the inner ball track 31, the center lines of the respective ball tracks are shown in fig. 1 in dashed lines, which extend equidistant from the associated

track base lines

23 and 33. In this case, the path of the ball track is composed of a plurality of segments in the axial direction, which have different radii and slopes. The outer ball track 21 and therefore its center line Sa have a concavely curved section on the inner side, wherein the ball track 21 then begins to widen in the region of the balls 40 in the direction of the opening 60. The widening is made up, for example, of a plurality of straight or curved segments.

Likewise, the inner ball track 31 and thus its center line Si have a convexly curved section on the outer side, wherein the ball track 31 widens in the region of the balls 41 in the direction of the connecting section 61. The widening can likewise consist of a plurality of straight or curved segments. The centre line Si of the inner ball track 31 and the centre line Sa of the outer ball track Sa intersect in a mirror plane Z, which in the embodiment of fig. 1 coincides with the joint centre plane E. However, depending on the position of the tolerance bands of the joint, the mirror plane Z may also lie beside the joint center plane E.

According to the invention, the two center lines Sa and Si are not mirror-symmetrical with respect to the mirror plane Z, whereas the inner ball track 31 is not a direct image of the outer ball track 21. Fig. 2 shows the centre line Si' of the mirror image of the inner ball track 31 on the mirror plane Z and it can be seen that the track of the mirror image inner section of the inner ball track 31 does not correspond to the track of the outer section of the outer ball track 21. The mirrored inner section of the inner ball track 31 is wider than the outer section of the outer ball track 21. This has the positive effect, in particular in the case of joints 10 which are bent at a maximum bending angle relative to conventional constant velocity universal joints, that is to say the distance between the outer ball track 21 and the inner ball track 31 is reduced.

Fig. 3 shows the joint 10 in the case of maximum deflection at a bending angle Omega. The angle Omega lies in the range of 53 deg., or preferably even in the range of 54 deg.. This view is through section B-B of the joint of fig. 14. In this position of the joint 10, the balls 40 partially protrude from the joint journal of the joint outer part 20 and are held there via three points. A first contact area 80 is formed between the balls 40 and the outer section of the outer ball track 21. A second contact area 81 is formed between the ball 40 and the inner section of the inner ball track 31. A third contact area 82 is formed between the balls 40 and the inner side of the cage windows 51 of the cage 50. Axial play, which accumulates during large deflections of the joint, exists between the joint outer part 20, the joint inner part 30 and the cage 50. In this case, the joint inner portion moves toward the opening 60 as the bending of the joint increases. In the conventional joint, the balls 40 are held between the three

contact regions

80, 81 and 82 with such a large clearance, resulting in generation of undesirable noise. Due to the greater lift of the inner section of the inner ball track 31, the balls 40 move toward the outer section of the outer ball track 21 and the inner side of the cage window 51 at large deflections, thereby reducing the play and thus reducing the generation of noise.

The different widening of the inner and outer ball tracks can be achieved in different ways. For example, if the widening is linear, the linear widenings may be configured to have different slopes with respect to the respective longitudinal axes La, Li. Fig. 4 shows the joint 10 in a maximally bent position, wherein the inner section 31i of the centre line Si of the inner ball track 31 extends at an angle Alpha i to the longitudinal axis Li of the joint inner part 30. A linear outer section 21a of the centre line Sa of the outer ball track 21 extends at an angle Alpha a to the longitudinal axis La of the joint outer part 20. In this case, angle Alpha a is greater than angle Alpha i.

In order to illustrate the greater widening of the inner section 31i of the inner ball track 31 in a more simplified manner, the trajectories of the inner and outer ball tracks of the first embodiment of the constant velocity universal joint according to the invention are shown in fig. 5. In the track pair shown, the centerline Si of the inner ball track and the centerline Sa of the outer ball track intersect at an intersection S. The intersection S simultaneously represents the intersection of the mirror plane Z and an axis L which extends at an angle of 90 ° to the mirror plane Z. In this case, the opening of the joint is located on the left side in fig. 5, and the connecting portion is located on the right side (see fig. 1). Thus, the left side is referred to as "outer" in the drawing, and the right side is referred to as "inner".

Both centre lines Sa, Si consist of a plurality of segments which overall form a wave-shaped track curve. The center line Si of the inner ball track has an outer section 31a which is formed convexly when viewed in the viewing direction of the inner ball track. On the right inner side, a linear inner section 31i is formed, which extends at an angle Alpha i relative to the axis L. Accordingly, the center line Sa of the outer ball track has an inner section 21a which is concavely formed when viewed in the viewing direction of the outer ball track. On the left outer side, a linear outer section 21a is formed, which extends at an angle Alpha a relative to the axis L. As already explained with respect to FIG. 4, Alpha a < Alpha i.

Therefore, the two center lines Sa, Si are not mirror-symmetrical with respect to the mirror plane Z. Thus, at the same distance a to the left and right of the intersection point S, the distances H, H between the axis L and the respective inner 31i and outer 21a sections are different. In contrast, the distance H between the axis L and the inner section 31i of the inner ball track is greater than the distance H between the axis L and the outer section 21a of the outer ball track. The distance a is defined by the fact that, in the case of a strongly curved joint and in particular in the case of a maximum curvature, the balls projecting from the outer part of the joint come into contact with the

contact regions

80, 81 and 82 in this region of the respective track curve (see fig. 3).

The trajectories of the inner and outer ball tracks of a second embodiment of the constant velocity universal joint according to the invention are shown in fig. 6, wherein the same form of view as in fig. 5 has been selected. The centre lines Sa, Si again consist of segments which overall form an S-shaped track curve. The centre line Si of the inner ball track again has an outer section 31a which is convexly formed when viewed in the viewing direction of the inner ball track. A curved inner section 31i is likewise formed on the inside, but its curvature is opposite to that of the outer section 31 a. The curved inner section 31i has a radius Ri.

Accordingly, the center line Sa of the outer ball track has an inner section 21i which is concavely formed as seen in the viewing direction of the outer ball track. A curved outer section 21a is formed on the outside, but its curvature is opposite to that of the outer section 21 i. The curved outer section 21a has a radius Ra. Relative to the mirror plane Z, neither of the two centerlines Sa, Si is mirror symmetric; in contrast, the radius Ri is smaller than the radius Ra. Whereby the distance H is smaller than the distance H.

In this case, the centerlines Sa, Si may take various suitable trajectories in the region of the intersection S, and in the transition to the inner section 31i of the centerline Si and to the outer section 21a of the centerline Sa. For example, the transition may be formed by a plurality of straight or curved track segments. Due to the special design of the constant velocity universal joint, further segments can also be connected to the free ends of the center lines Sa, Si in fig. 5 and 6, but these further segments will not be assigned to the path of the associated ball tracks if the balls do not pass these regions during operation of the joint.

The different distances H, H at the distance a to the intersection S can also be realized by other variations of the trajectory curve. Fig. 7, 8 and 9 show, for example, a trajectory variant in the case of a linear widening of the ball tracks, wherein the center lines Sa and Si of the outer and inner ball tracks of a track pair are shown in dashed lines, respectively. In contrast, the mirror image of the center line Si of the inner ball track with respect to the mirror plane Z is shown by a dotted line and is indicated by Si'. This results in a mirrored inner section 31i ' of the mirrored centre line Si ' of the inner ball track, by means of which the trajectory of the mirrored inner section 31 ' can be compared with the trajectory of the outer section 21a of the centre line Sa of the outer ball track.

Fig. 7 shows the trajectory of the inner ball track, in which a parallel displacement of the straight outer section 21a of the centre line Sa of the outer ball track to the right along the axis L produces a mirrored inner section 31i 'of the mirrored centre line Si' of the inner ball track. In this imaginary mirror image case, the mirror image inner section 31 i' is generally located closer to the connecting portion than the outer section 21 a. In contrast, fig. 8 shows a trajectory in which the center line Si' initially follows the trajectory of the center line Sa in the region of the intersection S and follows the trajectory of the outer section 21 a. After this, the slope of the inner segment 31 i' increases relative to the outer segment 21 a. Fig. 9 shows in principle also one such track profile, but with its mirror centre line Si 'following the trajectory of the centre line Sa before its slope increases in the region of the mirror inner section 31 i'.

Fig. 10 and 11 show possible trajectory variants in the case of a curved widening of the ball track. Fig. 10 shows the trajectory of the inner ball track, in which a parallel displacement of the curved outer section 21a of the centre line Sa of the outer ball track to the right along the axis L produces a mirrored inner section 31i 'of the mirrored centre line Si' of the inner ball track. In this imaginary mirror image case, the mirror image inner section 31 i' is generally located closer to the connecting portion than the outer section 21 a. In contrast, fig. 11 shows a trajectory in which the radius Ra of the curved outer section 21a corresponds to the radius Ri 'of the mirrored inner section 31 i'. However, the mirrored inner section 31 i' is rotated to the right generally about the intersection point S. In this case, the center of the circle to which the radius Ri of the mirror-image inner section 31i 'of the mirror-image center line Si' belongs is located closer to the connecting portion 61 than the center of the circle to which the radius Ra of the outer section 21a of the center line Sa of the outer ball track belongs.

The individual embodiments of these embodiments of the trajectory profile can also be combined with one another in a suitable manner. For example, the mirrored inner section 31 i' may rotate about the intersection point S and at the same time have a smaller radius than the outer section 21 a. The curved inner section 31 i' may also first follow the trajectory of the outer section 21a and then reduce its radius.

In general, the joint inner part may have a greater widening than the joint outer part compared to the open track area. Furthermore, this effect can be achieved by an outwardly open widening of the inner part of the plug being inserted earlier. Furthermore, this effect can be achieved by a longer insertion of the first preceding bend of the outwardly open track region of the joint inner part.

The constant velocity universal joint according to the invention can have different offsets, except for the track curves which do not run mirror-symmetrically. In particular, the cage offset is preferably combined with the ball track offset. 3 fig. 3 13 3 shows 3 a 3 section 3 a 3- 3 a 3 through 3 the 3 joint 3 of 3 fig. 3 12 3, 3 wherein 3 the 3 shaft 3 70 3 is 3 inserted 3 into 3 the 3 longitudinal 3 teeth 3 of 3 the 3 interior 3 of 3 the 3 joint 3 inner 3 part 3 30 3 and 3 the 3 joint 3 is 3 in 3 a 3 straightened 3 position 3. 3 The longitudinal axis La of the joint outer portion 20 now coincides with the longitudinal axis Li of the joint inner portion 30. The joint centerline E intersects the longitudinal axes La, Li at the joint center O.

The center of the curved track base line 23 of the outer ball track 21 lies on the longitudinal axis La, Li to the left of the joint center O, that is to say on the side of the opening 60 of the joint with respect to this joint center O. This intersection with the longitudinal axis La, Li is labeled OTa in fig. 13. The center of the curved track base line 33 of the inner ball track 31 lies on the longitudinal axis La, Li to the right of the joint center O, that is, on the side of the connecting portion 61 with respect to the joint center O. This intersection with the longitudinal axis La, Li is marked OTi.

The cage 50 has a spherical cage outer surface 53 which abuts on the spherical joint inner surface 25 of the joint outer part 20. Furthermore, the cage 50 has a spherical cage inner surface 54 which abuts on the spherical joint outer surface 35 of the joint inner part 30. The center of the curved cage outer surface 53 lies on the longitudinal axis La, Li to the left of the joint center O, that is to say on the side of the opening 60 of the joint with respect to this joint center O. This intersection with the longitudinal axis La, Li is marked OCa. The center of the curved cage inner surface 54 is located on the longitudinal axis La, Li to the right of the joint center O, that is, on the side of the connecting portion 61 of the joint with respect to the joint center O. This intersection with the longitudinal axis La, Li is labeled OCi in fig. 13.

In this case, intersection points OTa and OTi are preferably located at the same distance from joint center O. The same applies to the intersections OCa and OCi. However, the intersection points OCa and OCi are located closer to the joint center O than the intersection points OTa and OTi, that is, the ball track offset is greater than the cage offset.

List of reference numerals:

10 constant velocity universal joint, joint

20 outer part of joint

21. 22 outer ball track

Inner section of 21i outer ball track

21a outer section of the outer ball track

23. Track base line of 24 outer ball tracks

25 inner surface of joint

30 inner part of joint

31. 32 inner ball track

Inner section of ball track in 31i

Mirror image inner section of ball track in 31i

31a outer section of the ball track

33. 34 track base line of ball track

35 outer surface of joint

36 longitudinal tooth

40. 41 ball

50 holding rack

51. 52 cage window

53 outer surface of cage

54 cage inner surface

60 opening

61 connecting part

70 shaft

80. 81, 82 contact area

L axis

Longitudinal axis of outer part of La joint

Longitudinal axis of the inner part of the Li-joint

Center plane of E joint

S intersection point

Z mirror plane

Center of O joint

OCi intersection of inner faces of cage

Intersection of outer side surfaces of OCa cage

Intersection of ball tracks in OTi

OTa intersection of outer ball tracks

Center line of Si inner ball track

Mirror image center line of Si' inner ball track

Center line of Sa outer ball track

Radius of inner section of Ri inner ball track

Radius of mirror image inner section of Ri' inner ball track

Radius of outer section of Ra outer ball track

Claims

1. Constant velocity universal joint (10) for transmitting torque, comprising: a joint outer portion (20) having a plurality of outer ball tracks (21; 22); a joint inner portion (30) having a plurality of inner ball tracks (31; 32); torque-transmitting balls (40; 41) which are each guided in a track pair formed by the outer ball track (21; 22) and the inner ball track (31; 32); and a cage (50) which accommodates the balls (40; 41) in cage windows (51; 52) and holds them in a common joint center plane (E) in the event of straightening of the constant velocity universal joint (10), wherein the outer ball tracks (21; 22) have a center line (Sa) and track base lines (23; 24) which run equidistantly to the center line, and the inner ball tracks (31; 32) have a center line (Si) and track base lines (33; 34) which run equidistantly to the center line, wherein the joint outer part (20) has a longitudinal axis (La) and openings (60) and connecting parts (61) which lie axially opposite one another, and the center line (Sa) of the outer ball tracks (21; 22) has at least one concavely curved inner section (21i) and outer sections (21a) which lie respectively opposite the inner section, the outer section (21a) widens in the direction of an opening (60) of the joint outer part (20) relative to the longitudinal axis (La) of the joint outer part (20), while the center line (Si) of the inner ball track (31; 32) has at least one convexly curved outer section (31a) and inner sections (31i) respectively opposite the outer sections, the inner sections (31i) widening in the direction of a connecting section (61) of the joint outer part (10) relative to the longitudinal axis (La) of the joint outer part (20) and, with maximum deflection of the constant velocity universal joint (10), the balls (40) contacting the outer sections (21a) of the ball tracks (21; 22) and the inner sections (31i) of the inner ball tracks (31; 32),

characterized in that, in the case of the constant velocity universal joint (10) being straightened, the centerlines (Si; Sa) of the outer ball tracks (21; 22) and the inner ball tracks (31; 32) of a track pair intersect at an intersection point (S) and are in this case not mirror-symmetrical with respect to a mirror plane (Z) through this intersection point (S), wherein the mirror plane (Z) lies in or is parallel to the joint center plane (E), and the inner section (31i) of the centerline (Si) of the inner ball tracks (31; 32) is widened relative to the longitudinal axis (La) of the joint outer part (20) more than the outer section (21a) of the centerline (Sa) of the outer ball tracks (21; 22).

2. The constant velocity universal joint according to claim 1,

characterized in that, in addition to the inner section (21 i; 31i) and the outer section (21 a; 31a), the centre line (Sa) of the outer ball track (21; 22) and the centre line (Si) of the inner ball track (31; 32) have further sections which are connected to the inner section (21 i; 31i) and/or the outer section (21 a; 31a), respectively.

3. The constant velocity universal joint according to claim 2,

characterized in that the other segments are rectilinear or curved.

4. The constant velocity universal joint according to any one of claims 1 to 3,

characterized in that an outer section (21a) of the centre line (Sa) of the outer ball track (21; 22) and an inner section (31i) of the centre line (Si) of the inner ball track (31; 32) are widened linearly with respect to the longitudinal axis (La) of the joint outer part (20).

5. The constant velocity universal joint according to claim 4,

characterized in that the slope of the inner section (31i) of the centre line (Si) of the inner ball track (31; 32) is greater than the slope of the outer section (21a) of the centre line (Sa) of the outer ball track (21; 22) with respect to the longitudinal axis (La) of the joint outer portion (20).

6. The constant velocity universal joint according to any one of claims 4 and 5,

characterized in that, when a mirror image of the centre line (Si) of the inner ball track (31; 32) is made on the mirror plane (Z), the entire mirror image inner section (31i ') of the mirror image centre line (Si') of the inner ball track (31; 32) is closer to the connecting portion (61) than the entire outer section (21a) of the centre line (Sa) of the outer ball track (21; 22).

7. The constant velocity universal joint according to any one of claims 1 to 3,

characterized in that an outer section (21a) of the center line (Sa) of the outer ball track (21; 22) widens curvedly with a radius (Ra), and an inner section (31i) of the center line (Si) of the inner ball track (31; 32) widens curvedly with a radius (Ri).

8. The constant velocity universal joint according to claim 7,

characterized in that the radius (Ri) of the inner section (31i) of the centre line (Si) of the inner ball track (31; 32) is smaller than the radius (Ra) of the outer section (21a) of the centre line (Sa) of the outer ball track (21; 22).

9. The constant velocity universal joint according to any one of claims 7 and 8,

characterized in that, when a mirror image of the centre line (Si) of the inner ball track (31; 32) is made on the mirror plane (Z), the centre of the circle to which the radius (Ri) of the mirror image inner section (31i ') of the mirror image centre line (Si') of the inner ball track (31; 32) belongs is closer to the connecting portion (61) than the centre of the circle to which the radius (Ra) of the outer section (21a) of the centre line (Sa) of the outer ball track (21; 22) belongs.

10. Constant velocity universal joint according to one or more of claims 1 to 9,

characterized in that the longitudinal axis (La) of the joint outer part (20) and the joint center plane (E) intersect at the joint center O, and the cage (50) has a spherical cage outer surface (53) and a spherical cage inner surface (54), wherein the spherical cage outer surface (53) is in surface contact with the spherical joint inner surface (25) of the joint outer part (20) and the spherical cage inner surface (54) is in surface contact with the spherical joint outer surface (35) of the joint inner part (30), and the centers (OCi; OCa) of the spherical cage inner surface (54) and the spherical cage outer surface (53) are located on the longitudinal axis (La) on opposite sides of the joint center (O).

11. The constant velocity universal joint according to claim 10,

characterized in that the distance between the center (OCi; OCa) of the spherical cage inner surface (54) and the spherical cage outer surface (53) and the joint center (O) is equal.

12. Constant velocity universal joint according to one or more of claims 1 to 11,

characterized in that a longitudinal axis (La) of the joint outer portion (20) and the joint center plane (E) intersect at the joint center O, and that a center (OTa) of the concave inner section (21i) of the outer ball track (21; 22) and a center (OTi) of the convex outer section (31A) of the inner ball track (31; 32) are on the longitudinal axis (La) on opposite sides of the joint center (O).

13. The constant velocity universal joint according to claims 10 and 12,

characterized in that the distance between the center (OTa) of the concave inner section (21i) of the outer ball track (21; 22) and the center (OTi) of the convex outer section (31A) of the inner ball track (31; 32) and the joint center (O) is greater than the distance between the center (OCi; OCa) of the spherical cage inner surface (54) and the spherical cage outer surface (53), respectively, and the joint center (O).